Dns Component

Async DNS resolver.

The main point of the DNS component is to provide async DNS resolution. However, it is really a toolkit for working with DNS messages, and could easily be used to create a DNS server.

Basic usage

The most basic usage is to just create a resolver through the resolver factory. All you need to give it is a nameserver, then you can start resolving names, baby!

$loop = React\EventLoop\Factory::create();
$factory = new React\Dns\Resolver\Factory();
$dns = $factory->create('8.8.8.8', $loop);

$dns->resolve('igor.io')->then(function ($ip) {
    echo "Host: $ip\n";
});

$loop->run();

But there's more.

Caching

You can cache results by configuring the resolver to use a CachedExecutor:

$loop = React\EventLoop\Factory::create();
$factory = new React\Dns\Resolver\Factory();
$dns = $factory->createCached('8.8.8.8', $loop);

$dns->resolve('igor.io')->then(function ($ip) {
    echo "Host: $ip\n";
});

...

$dns->resolve('igor.io')->then(function ($ip) {
    echo "Host: $ip\n";
});

$loop->run();

If the first call returns before the second, only one query will be executed. The second result will be served from cache.

Custom cache adapter

By default, the above will use an in memory cache.

You can also specify a custom cache implementing CacheInterface to handle the record cache instead:

$cache = new React\Cache\ArrayCache();
$loop = React\EventLoop\Factory::create();
$factory = new React\Dns\Resolver\Factory();
$dns = $factory->createCached('8.8.8.8', $loop, $cache);

See also the wiki for possible cache implementations.

Install

The recommended way to install this library is through Composer. New to Composer?

This will install the latest supported version:

$ composer require react/dns:~0.4.0

If you care a lot about BC, you may also want to look into supporting legacy versions:

$ composer require "react/dns:~0.4.0|~0.3.0"

More details and upgrade guides can be found in the CHANGELOG.

License

MIT, see LICENSE file.

References

• RFC 1034 Domain Names - Concepts and Facilities
• RFC 1035 Domain Names - Implementation and Specification